A cuddly cub has been born. We have pictures and a big comeback story. A national treasure, a wildfire at yosemite national park. Thousands of people are being evacuated. And now, the governor of california has been forced to take an extreme measure. Abc's neal karlinsky is right there in groveland, california. Neal, good morning. Reporter: Dan, good morning. California's governor has declared a state of emergency, for the city of san francisco, 150 miles from here, because of the threat to the power and water supply. Power and water lines for san francisco, apparently run right through here. And they are now in danger because of this fire. This morning, fire teams are grappling with a seemingly insurmountable challenge. Get the top of the tree. Reporter: To take on this massive wildfire, in steep, rugged terrain, before it reaches the heart of one of most's most press teen treasures. Yosemite, with its waterfalls and famed peaks, like el capitan, are still open. And the landmarks remain untouched. But the rest of the park is burning. And firefighters have dug in to stop it to get it from going any further. It's enormous impact. We have a major holiday coming up. The last holiday of the season. The last big weekend of the season. Yes, major impact to people who live here and make their lives here. Reporter: The teams on the front lines have their orders, protect yosemite. But it is dangerous work. You know where your safety zone is? Your safety zone is down the road about four miles. It's a four-minute drive from this point right here. Reporter: They are optimistic but cautious. If we can hold this piece here, we may be successful in keeping it out of this part of yosemite. We're going to give it our best shot. Reporter: Along the other area, homes that have been evacuated. Residents have been lucky so far. But they're nervous, too. We're ready to go as soon as they give us the mandatory evacuation. I'm scared but not overly concerned at this point. Reporter: Now, a stunning 125,000 acres. The fire is reported to be 5% contained. That's up from just 1% a day earlier. Bianna? Neal, our thanks to you.

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